Tuesday, October 30, 2007

First I'll note that Behind The Net has updated as of Oct. 29, and I've also passed along a lengthy list of requests for other stats to be added to the site.

We'll see how that goes.

I've looked at defensive performance almost ad nauseam on this site in the past; call it my own little fascination, if you will. The greatest thing about a resource like BtN is that we can now measure what was previously unquantifiable (other than with the extremely limited plus-minus figure), and since I've always had a soft spot for the unheralded defensive defenders, that makes me giddy.

To me, many statheads make this far more complicated than it has to be: On some basic level, defensive performance simply comes down to playing the most minutes without having a goal go in your net. Period.

The leaders and the bottom feeders, 13 per cent of the way through 2007-08.

Defencemen with best 5-on-5 goals against average (among top 100 in ice time):

NAME

TEAM

GP

TOI/60

Q.COMP

GAON/60

1

ROSTISLAV KLESLA

CBJ

10

15.57

0.08

0.77

2

DEREK MORRIS

PHX

9

16.61

0.23

1.2

3

DANIEL GIRARDI

NYR

10

14.75

0.05

1.22

4

KENT HUSKINS

ANA

13

13.99

-0.09

1.32

5

JAROSLAV MODRY

L.A

12

14.61

-0.05

1.37

6

ADRIAN AUCOIN

CGY

11

15.9

-0.1

1.37

7

ANDREJ MESZAROS

OTT

10

16.28

-0.1

1.47

8

NICKLAS LIDSTROM

DET

12

16.03

0.34

1.56

9

BRIAN RAFALSKI

DET

12

15.79

0.31

1.58

10

BRETT LEBDA

DET

12

12.58

-0.1

1.59

11

BRAYDON COBURN

PHI

9

16.49

0

1.62

12

TOBIAS ENSTROM

ATL

11

13.39

0.07

1.63

13

KIMMO TIMONEN

PHI

9

16.21

0.12

1.64

14

F. BEAUCHEMIN

ANA

13

16.21

0.16

1.71

15

CHRIS PRONGER

ANA

13

15.74

0.11

1.76

16

DUNCAN KEITH

CHI

11

17.94

0.17

1.82

17

ANDREW FERENCE

BOS

10

16.35

-0.07

1.83

18

DION PHANEUF

CGY

11

17.68

0

1.85

19

ZDENO CHARA

BOS

10

16.07

0.24

1.87

20

ROMAN HAMRLIK

MTL

10

15.7

-0.05

1.91

By all accounts, big Rusty Klesla is having the year everyone in the Columbus organization thought he would when he was picked fourth overall in 2000. (Unfortunately many of those souls are no longer around to see it.)

That he (and a Coyotes defenceman!) lead all minute munching blueliners in goals against per 60 minutes played is pretty darn significant if you ask me.

Also noteworthy is the fact there are quite a few guys on here who play on struggling teams, namely rookie Tobias Enstrom with those poor Thrashers.

Derek Morris deserves a medal or something: He's played big minutes against brutal opposition on what is easily the worst team in the league, yet the puck's never going in when he's on the ice.

Honestly, does anyone know what's going on in Phoenix?

Defencemen with worst 5-on-5 goals against average (among top 100 in ice time):

NAME

TEAM

GP

TOI/60

Q.COMP

GAON/60

1

KEVIN BIEKSA

VAN

11

13.65

0.09

4.8

2

TREVOR DALEY

DAL

10

15.07

0.17

4.78

3

ALEXEI ZHITNIK

ATL

11

14.3

-0.11

4.58

4

LUBOMIR VISNOVSKY

L.A

12

15.34

0.08

4.56

5

HENRIK TALLINDER

BUF

10

14.64

0.23

4.51

6

MATT GREENE

EDM

12

13.81

-0.07

4.35

7

BRETT CLARK

COL

11

15.22

0.2

4.3

8

BRENT BURNS

MIN

11

15.58

0.06

4.2

9

ROB BLAKE

L.A

12

13.27

0.19

4.14

10

J-M LILES

COL

11

13.81

-0.1

3.95

11

KIM JOHNSSON

MIN

11

15.24

0.04

3.94

12

SCOTT HANNAN

COL

11

17.07

0.22

3.83

13

BRYAN ALLEN

FLA

11

15.72

0.05

3.82

14

DAN HAMHUIS

NSH

10

15.88

0.04

3.78

15

RYAN WHITNEY

PIT

10

14.36

0.02

3.76

16

FRANK KABERLE

CAR

11

13.05

0.03

3.76

17

GARNET EXELBY

ATL

11

16.04

-0.05

3.74

18

RADEK MARTINEK

NYI

9

16.08

0.01

3.73

19

BRENDAN WITT

NYI

9

16.22

0

3.7

20

IAN WHITE

TOR

12

13.57

0

3.68

21

KYLE MCLAREN

S.J

10

14.68

-0.06

3.68

So much for my crowing about the year Brent Burns has had in Minnesota.

Kevin Bieksa's really been having a tough go of it in Vancouver, apparently feeling the pressures that go along with that new big deal. Last year, they were calling him Jovo Jr. out West in reference to the recently departed ex-Canuck Ed Jovanovski, but now Bieksa's looking an awful lot like the Jovo Sr. of today.

Big, young rearguards like Matt Greene and Garnet Exelby are getting relatively easy minutes and still being punished, while it's been a terrible season for Alexei Zhitnik (pair him with Enstrom maybe?).

Players like Henrik Tallinder, Scott Hannan and Kim Johnsson were all leaders in this category last season, so it's been quite a swing for them. All three get the tough assignments and have been beaten up a bit.

N.B. Before the message boards go bonkers with stuff like 'Beaksa's the worstest!' and the like, it's worth noting that these are only defenders from the Top 100 in minutes played so far. Among all 227 defencemen who have played this season, Bieksa's 4.8 GA/60 is 12th worst, with players like Ladislav Smid (8.01), Maxim Kondratiev (6.36), Anders Eriksson (6.17) and Steve McCarthy (6.01) all pulling up the real rear.

Smid is the worst among all players who have played at least 40 5-on-5 minutes, while Derek Roy (6.33) is worst among those with 100+. Buffalo's defensive numbers are way off last year's pace, and Chris Drury's doing just fine in the Big Apple so far.

To me, many statheads make this far more complicated than it has to be:

The reason we do that is that this is a more complicated question than you are making it out to be. How many goals you let in is not just a function of your own performance. It's also a function of the performance of the teammates you were on the ice with, and the performance of the opposing players you were on the ice with. The stats try to account for this, but they do so in a problematic way.

It tries to measure the quality of your teammates and your opponents by how they perform, using the same metric. Of course, how each of those guys perform is also affected not only by the other guys on the ice are doing, but also by your performance. Given that Andy MacDonald was on the ice more than 90% of the time that Teemu Selanne was on the ice, trying to separate their effects is extremely difficult.

You have a system in which there are complicated interactions between a number of moving pieces. There are statistical tools that can be used to try to account for this. They rely upon the concept of recursion, and the Bradley-Terry method is a good example. This is used in KRACH, or Ken's Rankings for American College Hockey. More information on it can be found in the KRACH FAQ.

If you don't use some form of recursion, you can't separate out the pollution of the various interactions. You can rig up the system so that the numbers come out looking like they do now, and can be analyzed just like they are now. There's no reason that interpretations of the data need to be any more complicated. Generating the data does have to be more complicated.

Yah, but Mirtle, then it is a barely meaningful question dressed up as a serious one--because we all know people will read this and think "defensive prowess/liability", and that your question (who was on the ice for the most goals against) can't really get at that.

One of the most notable variables here is save percentage, of course, and that is unaccounted for by these stats.

I'm not exactly comparing the 80th defender to the 91st. There's a huge separation here between the top and bottom, one that can't be accounted for, or eliminated, but factoring in teammates, goaltenders or the like.

This data tells us the kind of year Kevin Bieksa is having, and the kind of year Rusty Klesla is having, and no amount of rejigging will change that.

Derek Morris, the Coyotes have been telling us, is having a great year, but have we seen a single statistic this season telling us so?

Is it perfect? Heck, no. But I find it useful (keeping in mind the limitations) and others do, too.

Is it perfect? Heck, no. But I find it useful (keeping in mind the limitations) and others do, too.

Yes, but how useful is it? We already knew that Derek Morris was doing pretty well. That's indicated by +4 on a very bad team, using the old, crude plus/minus system. This stat isn't telling us very much that looking at less complicated stats with a critical eye wasn't telling us. In roughly the same way, we can tell that Kevin Bieksa certainly isn't having a good year.

Given its limitations, this stat isn't really improving our knowledge. It simply gives the illusion of improving our knowledge.

I kind of agree with all that--but I think that it leads you beyond your last stated question, insofar as you are now introducing evidence to suggest "what kind of year players are having".

My point is simply that you and the statheads _are_ asking the same question, and thus more sophisticated approaches give better answers to the same question. But this data is still useful, to a point, in answering that question, if one is willing to bring some obvious interpretive tools to bear on the raw data, and to concede it useful from distinguishing molehills from mountains, but nothing more fine tuned than that.

Anyways, I digress, because I am, well, starting to make a mountain out of a molehill.

But this data is still useful, to a point, in answering that question, if one is willing to bring some obvious interpretive tools to bear on the raw data, and to concede it useful from distinguishing molehills from mountains, but nothing more fine tuned than that.

That's all I'm doing guys; not reinventing the wheel here. I wrote this post in 10-15 minutes.

If someone else wants to do a more detailed analysis, have at it. I'm happy with what's here.

Respectfully, I must disagree with J. Michael Neal. The point of these stats is to give a coarse estimate of a player's performance, the contribution of his teammates, and the level of competition he faces. We also want to keep the overall metrics as simple as possible.

Once you introduce recursion or power rankings into the mix, you lose the relationship between the data you collect and the final statistic.

If you wanted a better way to measure a player's performance, I wouldn't suggest for a second that more computation is the way to go.

As with baseball, football and basketball, the key would be to increase your observations of the actual game. We would want to know who has the puck at all times, where it is, and lots of information about passing and positioning.

Recursion's not going to get you there. BTW, if you'd like to run an alternate algorithm on the dataset, I'd be happy to send it to you.

Respectfully, I must disagree with J. Michael Neal. The point of these stats is to give a coarse estimate of a player's performance, the contribution of his teammates, and the level of competition he faces. We also want to keep the overall metrics as simple as possible.

Sure. Is this giving us a better coarse estimate than even simpler stats would give us? My speculation is that simply taking (Goals while on ice/Team's total goals allowed)/(Average time on ice/60) would give us almost as good an estimate.

Sure. Is this giving us a better coarse estimate than even simpler stats would give us? My speculation is that simply taking (Goals while on ice/Team's total goals allowed)/(Average time on ice/60) would give us almost as good an estimate.

You: GAON/(GAON+GAOFF)/TOI.

BtN: GAON/TOI - GAOFF/TOFF.

I'm not sure there's much difference in the significance of the two statistics.

But the point of the second one is pretty basic: to show the difference in a team's +/- when a guy is on the ice, and when he's off the ice.

It's expressed in goals per game, which is something most people will wrap their heads around without complaining about math.

The other point of this site is that I am not trying to do something secret and proprietary and make money off this like hockeyanalysis or thehockeyrating (etc) do. Rod is able to check my numbers and make sure they make sense, and if somebody wants to come up with improved statistics, I'm happy to zip up the entire database and send it to them.

The NHL feed isn't the most reliable thing in the world. Game 20107 has no data (CAR-PHI), for example, and if the past is any guide, it will never get fixed. Last year, the Rangers summaries almost never showed the goalie playing in the 3rd period. etc, etc...I just expect them to make mistakes...

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About Me

James has covered the NHL and the game of hockey since 2004, beginning with this website and continuing with The Globe and Mail (2008-16) and The Athletic. He is a member of the Professional Hockey Writers' Association, a long-time radio analyst with TSN and was the NHL network manager at SB Nation from 2008 to 2010. A graduate of Thompson Rivers and Ryerson universities, James grew up in Kamloops, B.C. as a season ticket holder in the Blazers' glory years.

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